Southeastern Biologist Discovers New Species of Crocodile

Above image, from left, with the new species at St. Augustine Alligator Farm Zoological Park: Jen Brueggen, park social media manager; Caleb McMahan; Christopher Murray; and John Brueggen, park director.

It has been a while since anyone has found a new crocodile. Thanks to the research of Southeastern Assistant Professor of Biology Christopher Murray and his colleague and former Southeastern classmate Caleb McMahan, that is no longer the case.

Southeastern Biological Sciences Department Head Christopher Beachy said that in an average year, worldwide there are many species of reptile described; however, most of these are snakes or lizards.

“Discovery of new species is not often a case of being in nature, seeing something remarkable, and exclaiming ‘Wow! This is an entirely new species,’” said Beachy. “New species are described mostly when experts, like Dr. Murray, are involved. We’re especially excited that this work began when Dr. Murray was studying to complete his master’s degree at Southeastern. That this has come to completion now that he is a tenure-track faculty member speaks to the quality of the training our graduate students receive. It also speaks to the international reputation that many of our faculty have. We’re very proud of that.”

slu_crocodile
Pictured is the Crocodylus halli, a new species of freshwater crocodile from Papua
New Guinea. This new species was previously thought to be a population of
Crocodylus novaeguineae, but variation, including cranial shape, indicates that
it is a distinct lineage. The live specimen shown here was photographed at St.
Augustine Alligator Farm Zoological Park. Copyright 2019 American Society of
Ichthyologists and Herpetologists.

Murray said the discovery is important because there are only about two dozen described species of extant crocodilian.

 

“Adding to the diversity of a group that small, being such large charismatic organisms with undiscovered species hiding right under our noses, is pretty rare,” he said. “This also sheds light on biogeographic patterns of other organisms in the area.” As a student working on his master’s degree in biology at Southeastern, Murray was reading several papers by the late Philip Hall, a crocodilian biologist who worked in the U.S. on alligators and in Papua New Guinea on a species of crocodile called the New Guinea Crocodile (Crocodylus navaeguineae).

“My thesis was on alligators in the U.S., but I recalled Philip Hall providing ecological and morphological evidence that the New Guinea crocs on the north side of the Central Highlands—a mountain range that runs east-west on the island of New Guinea—were different than the ones on the south side of the mountain range,” Murray explained. “For instance, they nested at different times of the year and had different osteoderm—the little bones on their backs—patterns.”

crocodile_skulls
Pictured is a sample photograph of skulls Murray and McMahan used in a technique called geometric morphometrics to analyze skull morphology. The results, when paired with published genetic data and the ecological data originally provided, diagnosed the northern and southern populations as being on independent evolutionary trajectories and warranted the description of a new species.

At the time, Murray’s roommate and friend McMahan, now working for The Field Museum in Chicago, was getting his master’s degree in evolutionary biology on fishes. Murray shared the details of his thesis with McMahan, and over the next several years they compiled data from New Guinea crocodile skulls from natural history museums, including The Field Museum, the Smithsonian National Museum of Natural History, Museum of Comparative Zoology at Harvard University, American Museum of Natural History, Queensland Museum, Louisiana State University Museum of Natural Science, and Florida Museum of Natural History.

“We took photos of the skulls and used a technique called geometric morphometrics to analyze skull morphology,” Murray said. “These results, when paired with published genetic data and the ecological data originally provided, diagnosed the northern and southern populations as being on independent evolutionary trajectories and warranted the description of a new species.”

From there, Murray and McMahan took their findings to the St. Augustine Alligator Farm Zoological Park in Florida to put their results to the test on live animals and on the ethno-artifacts on display.

chris_murray_american_crocodile
Christopher Murray poses in Costa Rica with his other study species, the American crocodile.

“We were pleasantly surprised that we could easily identify the two lineages even when moving or artistically altered,” Murray said. “So Caleb and I decided to name the species after Philip Hall, whose initial interests and observations spurred the description itself.”

Named Crocodylus halli, the new species is a freshwater crocodile inhabiting rivers and lagoons on the island of New Guinea, but Murray said more work is needed to assess its ecology and conservation status.

“Now that we know the evolutionary history of these species, we need to re-inform the conservation status of them given that the distribution has changed and conservation threats are different in different areas,” he said. “Caleb and I would take on aspects of that work, funding permitting.”

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A member of the Southeastern faculty since 2019, Murray’s teaching expertise lies in the fields of comparative morphology, physiological ecology, ecotoxicology, evolution, biogeography, philosophy of biology, and herpetology. He holds a bachelor of science degree in biology from Juniata College, a master of science in biology from Southeastern, and a doctorate in biology from Auburn University. He is a member of the American Society for Ichthyologists and Herpetologists; Alabama Partners in Amphibian and Reptile Conservation; and the Crocodile Specialist Group Species Survival Commission, IUCN.

By Tonya Lowentritt

 

 

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